Automatic fore/aft leveling trim function in a towable tillage implement

ABSTRACT

A system, apparatus and method for adjusting fore/aft level trim of the frame of a towed agricultural tillage implement utilize an electronic control unit that receives an input signal indicative of a desired depth of penetration of tillage tools operatively attached to the front and rear of the implement frame, and automatically computes a desired for/aft trim angle as a function of the desired depth input, and then adjusts the fore/aft trim of the implement frame by titling the frame toward the front or rear of the frame in accordance with the desired fore/aft trim angle computed from the desired depth input signal.

FIELD OF THE INVENTION

This invention relates generally to a towable agricultural tillageimplement, and more particularly to automatic trim adjustments to thefore/aft leveling of such an implement, to thereby facilitate operationof the towable tillage implement and provide improved seedbedconditions.

BACKGROUND OF THE INVENTION

Modern farming practices often utilize towable agricultural tillageimplements to prepare a seedbed providing optimal conditions forsubsequent planting of seed in the seedbed, proper germination andgrowth of the seed, and conservation of the soil in and below theseedbed. Such implements are configured to provide a seedbed having anumber of desirable conditions, including a uniform controlled depth, aflat and smooth floor at the bottom of the seedbed, and a relativelyeven surface finish.

To achieve these desired seedbed conditions, a number of factors must betaken into account in the design and set-up of the implement so that itwill operate properly with a given towing vehicle operating at a desiredspeed. Some of these factors are interdependent, and to date haverequired iterative adjustments to get the implement set just right forproducing the desired seedbed conditions.

Currently an operator must generally make some adjustments manually tothe implement, using turnbuckles or manually operated hydraulic controlsto get the implement properly set up for producing the desired seedbedconditions. The necessity for such manual adjustments result inundesirable delay and inconvenience for the operator. This isparticularly the case where such adjustments must be partially made byperson standing on the ground, rather than in the cab, or through theefforts of two people, one on the ground and one in the cab of thetowing vehicle.

It is common for such towable agricultural tillage implements to havefront and rear rows, or gangs, of tillage tools attached at front andrear ends of a frame of the towable implement. In such implements,adjustment of the depth of penetration of the front and rear rows oftillage tools is affected by the fore/aft level condition of the frame.For some types of implements and certain operating conditions, havingthe frame oriented substantially horizontally level with the groundunder the implement results in production of optimal desired seedbedconditions.

In the past, there have been a number of approaches utilized for settingthe fore/aft level of the frame generally horizontal to the ground underthe implement, and for maintaining the frame as level as possible duringoperation of the implement. Such leveling was accomplished typically bymanual adjustments made during initial set-up of the machine foroperation at a given depth of penetration of the tillage tools. Iftillage depth was increased or decreased, another iterative manual setupwas often required to reset the fore/aft level of the frame.

Some prior and current systems utilize manually operable turnbuckles toadjust the levelness of the frame. These adjustments are typicallycumbersome and time consuming. Other current systems utilize a manuallyoperable hydraulic frame-leveling cylinder to adjust the fore/aftlevelness of the frame. Systems using a manually operable frame-levelingcylinder offer considerable advantage in convenience and speed ofadjustment. But even where such systems are designed such that theleveling cylinder can be controlled by the operator from the seat of thetowing vehicle, making the required manual adjustments consumes moretime than is desirable, and introduces unwanted opportunity foradjustment error.

Some prior approaches have attempted to automate the process ofmaintaining the frame in a substantially level attitude throughout arange of operating depths of the implement. Some of these approachesutilize a mechanical linkage arrangement that is adjusted manuallyduring initial set-up of the implement to place the frame in a levelcondition. The linkage is configured such that, as the depth of theimplement is adjusted through a limited range of operating depths, thelinkage maintains the frame in a substantially level condition.

In another prior approach to automating fore/aft leveling of animplement frame, a mechanical leveling linkage includes one or morefore/aft leveling hydraulic cylinders that are plumbed into a hydrauliccircuit used to set the tillage depth in such a manner that the fore/aftleveling cylinders automatically adjust the levelness of the frame tomaintain the frame level as the tillage depth is changed, throughout arange of operating depths. Levelness is set by adjustments to themechanical linkage during an initial set-up procedure. The fore/aftleveling cylinders then operate automatically within the levelinglinkage to maintain the frame in a level position as the tillage depthis changed. This automatic operation of the leveling cylinders isachieved by selectively sizing the fluid capacity and flowcharacteristics of the fore/aft leveling cylinders, or by providing aflow divider/combiner, to maintain a fixed ratio of flow of hydraulicfluid to the fore/aft cylinders in proportion to the flow of hydraulicfluid in the tillage depth setting circuit, to thereby cause thefore/aft leveling cylinders to adjust the leveling linkage in a mannermaintaining the frame in a level position. While this system providesconsiderable improvement over previous approaches it still requires aninitial manual setup that is more cumbersome than is desirable, toproperly complete initial adjustment of the leveling linkage. Thisapproach also is limited to providing and maintaining a single, fixedadjustment of frame fore/aft level orientation that cannot be alteredwithout repeating the set-up procedure. Such an approach also requiresprecise sizing of the hydraulic components for proper operation.

While all of the above approaches to setting and maintaining thefore/aft level of an implement frame have been used with varying degreesof success in the past, they are more cumbersome and time consuming thanis desirable. Further improvements are desirable to simplify frameleveling adjustments through reducing manual adjustment, operatorinvolvement, and allowing any adjustments related to leveling to beconveniently carried out while the implement is in the field withoutresorting to complex readjustments when depth of operation is changed.

In addition, experience has shown that maintaining a perfectly levelframe orientation throughout the range of operating depths of a towabletillage implement may not always result in optimum seedbed preparationand operation of the implement. Experience has shown that sometimesoptimum performance requires that the frame be tilted from asubstantially level frame position. Optimal performance sometimesrequires that the frame be tilted to a trim angle other than level. Thedegree of such tilting or trim angle that is desirable for achieving adesired seedbed condition may be depth dependent, such that, as depth oftillage changes throughout the operating depth range of the implement,the trim angle needs to change to a greater or lesser degree of optimaltilt as a function of the tillage depth.

For example, in some types of implements, such as disk-type verticaltillage implements, optimal performance is sometimes achieved when theframe is tilted, or trimmed, slightly toward the front or the rearrather than being substantially horizontally level. In such implements,interaction of the tilled soil discharged by the leading, (i.e. front),gangs of tillage tools with the trailing, (i.e. rear), gangs of tillagetools can result in a less than optimal seedbed surface having ridgesand valleys that would hamper proper operation of seed plantingequipment. It is known, in such instances, that making small adjustmentsto the fore/aft trim of the tillage implement can correct this conditionand eliminate the ridges and valleys in the surface finish of theseedbed. The prior and current approaches described above to maintaininglevelness of the frame generally do not lend themselves to convenientlymaking such trim adjustments.

The degree of tilt or trim required is typically related to the desireddepth of the seedbed. Seedbed depth is consequently controlled by thedepth of penetration of the front and rear tillage tools. With priorapproaches, a desired smooth seedbed surface is often achieved only byan iterative process of: first, adjusting fore/aft trim to anessentially level position for uniform depth of penetration of the frontand rear tillage tools, as measured just behind the blades of the frontand rear tillage tools; second, adjusting the depth of penetration,verified again by measurement behind the blades of the front and reartillage tools; and then, trimming the fore/aft level to tilt the frameto the front or rear to achieve the desired seedbed surface finish forthe desired depth of penetration. Currently, some or all of theseadjustment steps must be performed by the operator manually whilestanding on the ground with the implement, rather than totally from thecab or seat of the towing vehicle.

It is desirable, therefore, to provide an improved system, apparatus andmethod for adjusting the fore/aft level trim of the frame of a towedagricultural tillage implement. It is further desirable that suchimprovements include provisions for making these adjustmentsautomatically, and without the necessity of the operator having todismount from the towing vehicle to accomplish the required adjustmentsfrom the ground.

SUMMARY OF THE INVENTION

The invention provides an improved system, apparatus and method foradjusting fore/aft level trim of the frame of a towable agriculturalimplement, through the use of an electronic control unit that receivesan input signal indicative of a desired depth of penetration of thetillage tools and automatically computes and adjusts the fore/aft tiltof the frame as a function of the desired depth input signal.

In one form of the invention, a towable tillage implement having anautomatic fore/aft level trim apparatus is provided, for engaging andacting upon a ground surface under the implement. The tillage implementincludes a frame defining forward and aft ends and upper and lowersurfaces of the frame. Front and rear tillage tools are attachedrespectively to the forward and aft ends of the frame. Ground supportwheels are operatively attached to the frame by a depth adjustingarrangement that includes a depth adjustment actuator for adjusting adepth of penetration of the front and rear tillage tools below theground surface. The implement also includes a hitch having an aft endpivotably attached to the forward end of the frame and a distal, orfree, end adapted for attachment at a drawbar height to the drawbar of atowing vehicle. The aft end of the hitch is operatively attached to theframe in a manner allowing the frame to be tilted along a fore/aft axisto adjust fore/aft trim of the frame.

The implement also includes a fore/aft trim angle adjusting actuatoroperatively attached between the hitch and the frame for tilting theframe at a trim angle along the fore/aft axis. A trim angle adjustmentpower source is operatively attached to the fore/aft trim actuator fordriving the trim actuator to adjust the trim angle. A trim angleposition sensor is operatively attached between the hitch and the framefor indicating a present value of the fore/aft trim angle, and providingan electrical output in the form of a present trim angle signal that isindicative of the present fore/aft trim angle of the frame. In someforms of the invention, the trim angle position sensor detects a presentvalue of a pivot angle between the frame and the hitch that isindicative of the present value of the fore/aft trim angle of the frame,and generates an electrical output in the form of a present trim anglesignal that is indicative of the present fore/aft trim angle of theframe.

A depth sensor is operatively attached to the implement for indicating apresent depth of penetration of at least one of the front and reartillage tools, and providing an electrical output in the form of apresent depth signal indicative of the present depth of penetration ofthe at least one tillage tool.

A control unit is operatively connected to the depth and the trim anglesensors respectively for receiving the electrical present depth andpresent trim angle signals from the depth sensor and the trim anglesensor. The control unit is also operatively connected to the trim angleadjustment power source to provide control of the trim angle adjustmentpower source for selectively driving the trim angle actuator to tilt theframe along the fore/aft axis to thereby change the present fore/afttrim angle of the frame. The control unit is further configured forreceiving a desired depth input and controlling the trim angle actuatorto provide a desired fore/aft trim angle of the frame corresponding tothe desired depth input signal.

In some forms of an implement, according to the invention, the controlunit selects a predetermined trim angle corresponding to the desiredseedbed depth input and controls the trim angle actuator power sourceusing the predetermined trim angle. In other forms of the invention, thecontrol unit of the implement computes a desired trim anglecorresponding to the desired depth input, and controls the trim angleactuator power source using the computed trim angle. In yet other formsof an implement, according to the invention, the desired depth input isan incremental adjustment a present depth of penetration.

In some forms of an implement, according to the invention, the trimangle adjusting actuator is a hydraulic cylinder, and the trim angleadjusting power source is an electrically controlled hydraulic powersource. The hydraulic cylinder may define a present cylinder stroke, andthe trim angle position sensor may indicate the present trim angle bydetecting a present absolute position of the present cylinder stroke. Inother forms of the invention, the trim angle adjusting actuator may bean electrically driven linear actuator, and the trim angle adjustingpower source is an electrical power source. The electrically drivenlinear actuator may define a present stroke length thereof, and the trimangle position sensor may indicate the present trim angle by detecting apresent absolute position of the present linear actuator stroke.

In another form of the invention, a system for adjusting the fore/afttrim of a towed tillage implement, such as the implement describedabove, is provided. The fore/aft trim adjustment system includes afore/aft trim angle adjusting actuator operatively attached between thehitch and the frame for tilting the frame at a trim angle along thefore/aft axis. A trim angle adjustment power source is operativelyattached to the fore/aft trim actuator for driving the trim actuator toadjust the trim angle, and a trim angle position sensor operativelyattached between the hitch and the frame for indicating a present valueof the fore/aft trim angle, and providing an electrical output in theform of a present trim angle signal indicative of the present fore/afttrim angle of the frame. The system also includes a depth sensoroperatively attached to the implement ter indicating a present depth ofpenetration of at least one of the front and rear tillage tools, andproviding an electrical output in the form of a present depth signalindicative of the present depth of penetration of the at least onetillage tool.

The system also includes a control unit operatively connected to thedepth sensor and the trim angle sensors for respectively receiving theelectrical present depth and present trim angle signals from the depthand trim angle sensors. The control unit is also operatively connectedto the trim angle adjustment power source to provide control of thepower source for selectively driving the trim angle actuator to tilt theframe along the fore/aft axis, to thereby change the present fore/afttrim angle of the frame. The control unit of the system for adjustingfore/aft trim is further configured for receiving a desired depth inputand controlling the trim angle actuator to provide a desired fore/afttrim angle of the frame corresponding to the desired depth input signal.

In some forms of an implement, according to the invention, the controlunit selects a predetermined trim angle corresponding to the desiredseedbed depth input and controls the trim angle actuator power sourceusing the predetermined trim angle. In other forms of the invention, thecontrol unit of the implement computes a desired trim anglecorresponding to the desired depth input and controls the trim angleactuator power source using the computed trim angle. In yet other formsof an implement, according to the invention, the desired depth input isan incremental adjustment to a present depth of penetration.

In some forms of a system according to the invention, for adjusting thefore/aft trim of an implement, the trim angle adjusting actuator is ahydraulic cylinder, and the trim angle adjusting power source is anelectrically controlled hydraulic power source. The hydraulic cylindermay define a present cylinder stroke, and the trim angle position sensormay indicate the present trim angle by detecting a present absoluteposition of the present cylinder stroke. In other forms of theinvention, the trim angle adjusting actuator may be an electricallydriven linear actuator, and the trim angle adjusting power source is anelectrical power source. The electrically driven linear actuator maydefine a present stroke length thereof, and the trim angle positionsensor may indicate the present trim angle by detecting a presentabsolute position of the present linear actuator stroke.

In another form of the invention, a method is provided for adjusting thefore/aft trim of a towed tillage implement using a fore/aft trimadjustment system, such as the implement and system according to aspectsof the invention described above. In one form of the invention, a methodfor adjusting the fore/aft trim of a towed implement frame includesautomatically tilting the frame in a fore/aft direction in response to aremotely generated signal computed as a function of a desired depthinput and a present fore/aft trim angle of the frame.

A method, according to the invention may include the steps of:operatively attaching a fore/aft trim angle adjusting actuator betweenthe hitch and the frame for tilting the frame at a trim angle along thefore/aft axis; operatively attaching a trim angle adjustment powersource to the fore/aft trim actuator for driving; the trim actuator toadjust the trim angle; operatively attaching a trim angle positionsensor between the hitch and the frame for indicating a present value ofthe fore/aft trim angle, and providing an electrical output in the formof a present trim angle signal indicative of the present fore/aft trimangle of the frame; operatively attaching a depth sensor to theimplement for indicating a present depth of penetration of at least oneof the front and rear tillage tools, and providing an electrical outputin the form of a present depth signal indicative of the present depth ofpenetration of the at least one tillage tool; and, operativelyconnecting a control unit to the depth sensor and the trim angle sensorfor respectively receiving the electrical present depth and present trimangle signals therefrom. The method may further include the additionalsteps of: operatively connecting the control unit to the trim angleadjustment power source to provide control of the trim angle powersource to cause the power source to selectively drive the trim angleactuator to tilt the frame along the fore/aft axis, and to therebychange the present fore/aft trim angle of the frame; receiving a desireddepth input at the control unit; and controlling the trim angle actuatorto provide a desired fore/aft trim angle of the frame corresponding tothe desired depth input signal.

Some forms of a method according to the invention may include selectinga predetermined desired trim angle corresponding to the desired depthinput, and automatically tilting the frame to the predetermined desiredtrim angle corresponding to the desired depth input. Some forms of amethod according to the invention may include computing a desired trimangle corresponding to the desired depth input and automatically tiltingthe frame to the computed trim angle. In some forms of a method,according to the invention, where the control unit computes a desiredtrim angle, and the present depth of penetration of tillage tools of theimplement is known, and the desired depth input is an indication of adesired incremental adjustment to the present depth of penetration ofthe implement, the method may include computing a desired trim anglecorresponding to the desired depth input incremental adjustment andautomatically tilting the frame to the computed trim angle.

Some forms of the invention may include receiving the desired depthinput from a location remote from the towable tillage implement. In someforms of the invention, the inputs from the operator, and functionalityof the control unit may utilize aspects of modern farm equipment, suchas an ISOBUS, or other applicable technology such that the operator mayutilize the invention for automatically adjusting fore/aft trim of atowable tillage implement while the operator remains positioned in thecab of the towing vehicle.

Other aspects, objects and advantages of the invention will be apparentfrom the following detailed description and accompanying drawings ofexemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings incorporated in and forming a part of thespecification illustrate aspects of the present invention and, togetherwith the description, serve to explain the principles of the invention.In the drawings:

FIG. 1 is a top view of an exemplary embodiment, according to theinvention, in the form of a towable tillage implement, attached to atowing vehicle;

FIG. 2 is an isometric view of a main frame of the implement of FIG. 1,and selected components of the implement mounted on or attached to themain frame;

FIG. 3 is a side view of the main frame of FIG. 2, with some elements ofthe frame and selected components cut away to better illustrate aspectsof the invention;

FIG. 4 is a top, partially schematic, view of the main frame of FIG. 2.Showing the location and connections of control elements of theinvention; and

FIG. 5 is an isometric view showing details of a fore/aft positionsensor mounting of the implement of FIG. 1.

While the invention will be described in connection with certainpreferred embodiments, there is no intent to limit it to thoseembodiments. On the contrary, the intent is to cover all alternatives,modifications and equivalents as included within the spirit and scope ofthe invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows an exemplary embodiment of the invention in the form of atowable tillage implement 10 attached to a towing vehicle 12 at adrawbar 14 of the towing vehicle 12. More specifically, FIG. 1 shows anexemplary embodiment of the invention in the form of a tandemagricultural disk 10, attached to a tractor 12 at the tractor drawbar14. The exemplary embodiment of the disk 10 also incorporates elementsof a system for adjusting fore/aft trim of a frame 16 of the disk 10,according to an exemplary embodiment of a method for practicing theinvention.

As shown in FIG. 1, the frame 16 of the exemplary embodiment of thetandem disk 10 is an assembly that includes a centrally located mainframe 18, and left and right wing frames 20, 22. The left and right wingframes 20,22 are pivotably attached to the main frame 18 in a mannerthat allows the wing frames 20,22 and tillage tools and wing supportwheels attached to the wing frames 20,22 to be folded above the mainframe 18 by hydraulic cylinders 24, 26 to facilitate movement of thedisk 10 from one field to another.

As shown in FIGS. 1-3, the main flume 18 defines forward and aft ends28,30, and upper and lower surfaces 32,34 of the main frame 10. Centersections of front and rear gangs of tillage tools 36,38 are respectivelyattached to the forward and aft ends 28,30 of the main frame 18. In theexemplary embodiment of the implement 10, the front and rear tillagetools are disks, but it will be understood that in other embodiments ofthe invention the tillage tools could take other forms. For clarity ofillustration, the tillage tools 36,38 are not shown in FIG. 2, and onlythe front tillage tool 36 is illustrated in FIG. 3.

As shown in FIGS. 1-3, the exemplary embodiment of the disk 10 includesfour ground support wheels 40 operatively attached to the main frame 18by a depth adjusting arrangement 42, that includes a pair of depthadjusting actuators in the form of hydraulic cylinders 44,46. The depthadjusting cylinders 44,46 are operatively attached at opposite endsthereof between the main frame 18 and a rock shaft 48 of the depthadjusting arrangement 42, in such a manner that extension and retractionof depth adjusting cylinders 44,46 causes the depth adjustingarrangement to raise and lower the main frame 18, to thereby adjust thedepth of penetration 50 below the surface 52 of the ground under thedisk 10.

As shown in FIGS. 1-3, the exemplary embodiment of the disk 10 alsoincludes a disk hitch 54 having an aft end 56 thereof that is pivotablyattached to the forward end 28 of the main frame 18, as indicated at 58.As shown in FIG. 3, this pivotable attachment allows the main frame 18and the hitch 54 to be pivoted with respect to one another about thepivot axis 58, through a pivot angle 59, as shown in FIG. 3. As will beunderstood from the description below, the pivot angle 59 is indicativeof the fore/aft trim angle 68 of the frame 18, and is used in someembodiments of the invention for detecting and controlling the fore/afttrim angle 68 of the frame 18. The hitch 54 also has a distal end 60that is adapted for attachment to the tractor drawbar 14, as indicatedat 62, at a drawbar height 64 above the ground surface 52. Attachment ofthe hitch 54 in this manner allows the main frame 18, and the wingframes 20,22 attached to the mainframe 18 to be tilted along a fore/aftaxis 66 in the manner illustrated schematically in FIGS. 2 and 3 toadjust a fore/aft trim angle 68 of the main frame 18 and consequently toadjust the fore/aft trim angle 68 of the entire frame 16.

A fore/aft trim angle adjusting actuator 70 is operatively connectedbetween the main frame 18 and the hitch 54 in such a manner that themain frame 18 can be tilted along the fore/aft axis 66, to therebyadjust the fore/aft trim of the mainframe 18 for setting the main frame18 at a desired degree of fore/aft trim angle 68. In the exemplaryembodiment, the fore/aft trim angle adjusting actuator 70 is a hydrauliccylinder, but in other forms of the invention other types of linear orrotary actuators, such as an electrically operated linear actuator or amotor could be utilized.

As shown in FIGS. 2 and 3, the fore/aft trim angle adjusting actuator 70of the exemplary embodiment is operatively attached between the mainframe 18 and the hitch 54 in a manner that, allows the fore/aft trimactuator 70 to perform a dual function. Specifically, one end of thefore/aft trim cylinder 70 is pivotably attached to the hitch 54 asindicated at 72. The other end 74 of the fore all trim cylinder 70 ispivotably attached to an articulated arm 76 of a hitch flexingarrangement 78 that allows the hitch 54 and main frame 18 to flex to alimited degree about the pivotable attachment 58 between the hitch 54and the main frame 18, so that the disk 10 can better follow the terrainwhile traversing hills or valleys in the ground surface 52. Thearticulated aim 76 has second and third pivotable connections 80,82 tothe main frame 18 and a forward end 83 of a longitudinally extendingcontrol rod 84. The opposite end 85 of the control rod 84 is attached tothe rock shaft 48 of the depth adjusting arrangement 42 with a pair ofsprings 86,88 that allow the limited pivotable movement about thepivotable attachment 58 joining the front of the main frame 18 to theaft end 56 of the hitch 54. With this arrangement, the fore/aft trimadjusting cylinder 70 serves as a passive link in the hitch flexingarrangement 78, in addition to its primary function of providingadjustment of the fore/aft trim angle 68 through extension andretraction of the cylinder 70. It will be appreciated that in otherembodiments of the invention the fore/aft trim adjustment actuator 70may be operatively attached between the main frame 18 and the hitch 54in a different manner, and not as part of a hitch flexing arrangement.

As shown in FIGS. 2-5, the exemplary embodiment of the disk 10 includesa trim angle position sensor 90 operatively connected between the hitch54 and main frame 18 for detecting a present value of the pivot angle 59between the frame 18 and the hitch 54 that is indicative of a present,value of the fore/aft trim angle 68 of the frame, and providing anelectrical output in the form of a present trim angle signal 103 that isindicative of the present fore/aft trim angle 68 of the main frame 18.It will be appreciated that, for a given hitch height 64, and depth 50,geometry of the disk components will result in a constant relationshipbeing established between the pivot angle 59 and the fore/aft trim angle68 of the disk frame 18. This relationship is advantageously utilized insome embodiments of the invention to provide a measurement of presentfore/aft trim angle 68 in a manner that is more straightforward thanmethods relying on other types of sensors, such as inclinometers, sonar,proximity sensors, or gauge wheels, etc., for determining andcontrolling the fore/aft trim angle 68.

As shown in FIGS. 3 and 5, in the exemplary embodiment of the invention,the trim angle position sensor 90 is integrated into a trim angle gaugearrangement 89, that includes a trim angle gauge dial 91, a trim anglegauge pointer 93, and a trim angle gauge link 94. The trim angle gaugedial and pointer 91,93 are both mounted at their aft ends on a commonpin 71 that attaches the forward end of the trim angle cylinder 70 tothe aft the 56 of the hitch 54, as indicated at 72 in FIG. 3. Morespecifically, the forward end of the cylinder 70, and the aft ends ofthe trim angle gauge dial and pointer 91,93 are all attached to a hairof mounting ears 95 extending upward from the aft end 56 of the hitch 54by the common pin 71. The cylinder 70 and the pointer 93 are freelypivotably attached to the mounting, ears 95 of the hitch 53 for pivotingmovement about the pin 71. The aft end of the trim angle gauge dial 91is fixed to the forward end of the trim angle cylinder 70 to pivot aboutthe pin 71 with the forward end of the cylinder 70, in such a mannerthat the dial 91 is held in a fixed alignment with an extension axis 73of the trim angle cylinder 70.

As further shown in FIGS. 3 and 5, the aft end of the trim angle gaugelink 94 is pivotably attached, together with the aft end of the trimangle cylinder 70, to attachment point 74 of the articulated arm 76 ofthe hitch flexing arrangement 78. The forward end of the trim anglegauge link 94 is pivotably attached to the aft end of the trim anglegauge pointer 93 at a location 96 that is offset from the point ofattachment 72 to the cylinder 70 and ears 95, in such a manner that thegauge link 94 causes the pointer 93 to move with respect to the gaugedial 91 as the cylinder 70 is extended and retracted. The dial 91 iscalibrated to provide a visual indication of the fore/aft trim angle 68of the frame 18, and whether the aft end 30 of the frame 18 is raised orlowered with respect to the forward end 28 of the frame 18.

The fore/aft trim angle sensor 90, in the exemplary embodiment, is arotary potentiometer having a body 97 attached to a bracket of one ofthe mounting ears 95 extending upward from the aft end 56 of the hitch54. A rotatable input arm 98 of the potentiometer 90 operatively engagesa slot 99 in the pointer 93 in such a manner that as the pointer 93moves with respect to the dial 91, the rotatable input arm 98 isrotated, through interaction with the slot 99 in the pointer 93, tothereby generate the electrical signal 103 that is indicative of thepresent trim angle 68 of the main frame 18. The exemplary embodimentillustrated in FIG. 5 also includes a tension spring 118 extending fromthe distal end of the input arm 98 to the aft end 56 of the hitch 54, tofacilitate tracking of the input arm 98 in the slot 99.

It will be appreciated that in practicing the invention, otherarrangements for providing the present trim angle signal arecontemplated, within the scope of the invention. For example, it is notnecessary in practicing the invention to have the trim angle sensor 90integrated into a trim angle gauge arrangement 89, in the mannerdescribed above. In some embodiments of the invention, the trim anglesensor 90 may be located at an alternate position on the implement 10,for detecting the pivot angle 59 between the frame 18 and the hitch 54about the pivot axis 58. In some embodiments of the invention, the trimangle sensor functionality may be incorporated into the trim angleactuator 70, by utilizing a so-called “smart actuator” that includes anintegral sensor for detecting a present stroke length of the actuatorthat is indicative of the present fore/aft trim angle 68 of the frame18.

As shown in FIG. 4, one of the depth control cylinders 46 includes acylinder extension sensor that serves as a depth sensor 100, providingan output electrical present depth signal 102 that is indicative of apresent depth of penetration 50 of the tillage tools 36,38 below thesurface of the ground 52. It will be appreciated that in otherembodiments of the invention other types of depth sensing arrangementsmay be attached to an implement for sensing depth in a different manner.In the exemplary embodiment, the degree of extension of the depthcylinders 44,46 is directly proportional to the operation of the depthadjusting, arrangement 42, and therefore provides a continuous indirectmeasurement of present depth of penetration 50 of the tillage tools36,38.

As shown in FIG. 4, the exemplary embodiment of the disk 10, and asystem and method of adjusting fore/aft trim angle 68 of the main frame18, also include a fore/aft trim angle control unit 104, and a trimangle adjustment power source 106. The trim angle adjustment powersource 106 in the exemplary embodiment 10 is an electrically controlledhydraulic power source operatively connected to supply hydraulic fluidto the fore/aft trim angle adjustment cylinder 70 in response toelectrical control signals 110 received from the fore/aft trim anglecontrol unit 104.

The control unit 104 of the exemplary embodiment is an electroniccontroller that is operatively connected by wires, or wirelessly, to thefore/aft trim position sensor 90 and the depth sensor 100, torespectively receive the present trim angle signal 103 and the presentdepth signal 102. The control unit 104 is configured to also receive adesired depth input 108, from an operator of the disk 10, indicating adesired depth of penetration 50 of the tillage tools 36,38 below theground surface 52. The control unit is further configured to provide acontrol signal 110 to the fore/aft trim angle adjustment power source106, corresponding to the desired depth input 108, for automaticallydriving the fore/aft trim angle cylinder 70 to tilt the main frame 18along the fore/aft trim axis 66 and thereby change the trim angle 68 ofthe frame 18 from present trim value corresponding to the present depth50 to a new present value of trim angle 68 corresponding to the desireddepth input 108.

In some embodiments of the invention, the control unit 104 is configuredto select a predetermined new fore/aft trim angle 68 corresponding tothe desired depth input 108, from predetermined values of fore/aft trimangle as a function of desired depth stored in memory within the controlunit 104. For example, if the operator indicates that he desires a depth50 of three inches, the control unit will search its memory and retrievea predetermined fore/aft trim angle 68 corresponding to a desired depthof three inches, and send an appropriate control signal 110 to thefore/aft trim angle power source 106 to drive the main frame 18 to thenew trim angle 68 corresponding, to the desired depth input 108.

In some embodiments of the invention, the control unit 104 is configuredto calculate a new trim angle 68 corresponding, to a desired depth input108, rather than using predetermined new trim angles stored in memory ofthe control unit 104. Some embodiments of a control unit 104, accordingto the invention, are configured such that the operator can input anincremental change in desired depth from a present depth 50 ofpenetration of the tillage tools 36,38, which the control unit 104 willuse to calculate a new trim angle 68 corresponding to the desiredincremental change. For example, an operator may input a desiredincremental change to reduce the desired depth by one inch from itspresent depth of penetration 50. If the disk 10 was set at a presentdepth 50 of four inches when the incremental change was inputted to thecontrol unit 104, the control unit 104 would compute a new desired trimangle corresponding to three inches of depth 50 and the fore/aft trimsystem 18 would automatically drive the fore/aft trim actuator 70 totilt the mainframe to the proper trim angle 68 for the new desired depthof three inches, without any further input or action by the operator.

It is contemplated that in a system, apparatus or method, according tothe invention, the inputs from the operator, and functionality of thecontrol unit may utilize aspects of modern farm equipment, such as anISOBUS, or other applicable technology such that the operator mayutilize the invention for automatically adjusting fore/aft trim of atowable tillage implement while positioned in the cab of the towingvehicle.

It will be understood that the present invention may he utilized toautomatically trim for/aft levelness of a towable tillage implement in amore convenient manner than has heretofore been possible, by eliminatingthe need for the repetitive, iterative approaches used in the past thattypically required manual adjustments of fore/aft trim by the operator,and in some instances required the assistance of a second person. Theinvention also allows far greater freedom and flexibility in fine tuningthe fore/aft trim of the towable implement, in the field, andessentially on-the-fly during operation of the implement. Whereas priorapproaches to fore/aft leveling were essentially limited to maintainingan implement frame in a single, horizontally level or other trimcondition set during an initial set-up operation, the invention allowsthe fore/aft trim of an implement to be adjusted in the field to utilizetrim angles other than the one set in the initial set-up, so that thetrim angle may be continually fine-tuned to whatever angle works best ina given field condition.

From the foregoing description of exemplary embodiments, those havingskill in the art will readily appreciate that the invention providessignificant advantages over prior approaches to adjusting fore/aft trimof a towed tillage implement.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) is to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention.Variations of those preferred embodiments may be apparent to thosehaving skill in the art upon reading the foregoing description. Theinventors expect skilled artisans to employ such variations asappropriate, and the inventors intend for the invention to be practicedotherwise than as specifically described herein. Accordingly, thisinvention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.It is specifically noted that, although the description herein wasdirected to practice of the invention in a towed agricultural implement,the invention is not limited to practice only in agricultural tillageequipment.

We claim:
 1. A system for adjusting fore/aft trim in a towed implementhaving a frame defining forward and aft ends and upper and lowersurfaces thereof, front and rear tillage tools attached respectively tothe forward and aft ends of the frame, ground support wheels operativelyattached to the frame by a depth adjusting arrangement that includes adepth adjustment actuator for adjusting a depth of penetration of thefront and rear tillage tools below a ground surface, a hitch having anaft end thereof pivotably attached to the forward end of the frame and adistal end thereof adapted for attachment at a drawbar height to atowing vehicle, with the aft end of the hitch being pivotably attachedto the frame in a manner allowing the frame to be pivoted through apivot angle with respect to the hitch for tilting the frame along thefore/aft axis to thereby adjust fore/aft trim of the frame, the fore/afttrim adjustment system comprising: a fore/aft trim angle adjustingactuator operatively attached between the hitch and the frame fortilting the frame at a trim angle along the fore/aft axis; a trim angleadjustment power source operatively attached to the fore/aft trimactuator for driving the trim actuator to adjust the trim angle; a trimangle position sensor operatively attached between the hitch and theframe for detecting a present value of the pivot angle between the frameand the hitch that is indicative of a present value of the fore/aft trimangle, and providing an electrical output in the form of a present trimangle signal indicative of the present fore/aft trim angle of the frame;a depth sensor operatively attached to the implement for indicating apresent depth of penetration of at least one of the front and reartillage tools, and providing an electrical output in the form of apresent depth signal indicative of the present depth of penetration ofthe at least one tillage tool; and a control unit operatively connectedto the depth sensor and the trim angle sensors for respectivelyreceiving the electrical present depth and present trim angle signalstherefrom; the control unit also being operatively connected to the trimangle adjustment power source to provide control thereof for selectivelydriving the trim angle actuator to tilt the frame along the fore/aftaxis to thereby change the present fore/aft trim angle of the frame; thecontrol unit being further configured for receiving a desired depthinput and controlling the trim angle actuator to provide a desiredfore/aft trim angle of the frame corresponding to the desired depthinput signal.
 2. The system of claim 1, wherein the control unit selectsa predetermined trim angle corresponding to the desired seedbed depthinput and controls the trim angle actuator power source using thepredetermined trim angle.
 3. The system of claim 1, wherein the controlunit computes a desired trim angle corresponding to the desired depthinput and controls the trim angle actuator power source using thecomputed trim angle.
 4. The system of claim 3, wherein the desired depthinput is an incremental adjustment to a present depth of penetration. 5.The system of claim 1, wherein the trim angle adjusting actuator is ahydraulic cylinder, and the trim angle adjusting power source is anelectrically controlled hydraulic power source.
 6. The system of claim1, wherein the trim angle adjusting actuator is an electrically drivenlinear actuator cylinder, and the trim angle adjusting power source isan electrical power source.
 7. A towable tillage implement for engagingand acting upon a ground surface under the implement, the tillageimplement comprising: a frame defining forward and aft ends and upperand lower surfaces thereof; front and rear tillage tools attachedrespectively to the forward and aft ends of the frame; ground supportwheels operatively attached to the frame by a depth adjustingarrangement that includes a depth adjustment actuator for adjusting adepth of penetration of the front and rear tillage tools below theground surface; a hitch having an aft end thereof pivotably attached tothe forward end of the frame and a distal end thereof adapted forattachment at a drawbar height to a towing vehicle, with the aft end ofthe hitch being pivotably attached to the frame in a manner allowing theframe to be pivoted through a pivot angle with respect to the hitch fortilting the frame along the fore/aft axis to thereby adjust fore/afttrim of the frame; a fore/aft trim angle adjusting actuator operativelyattached between the hitch and the frame for tilting the frame at a trimangle along the fore/aft axis; a trim angle adjustment power sourceoperatively attached to the fore/aft trim actuator for driving the trimactuator to adjust the trim angle; a trim angle position sensoroperatively attached between the hitch and the frame for detecting apresent value of the pivot angle between the frame and the hitch that isindicative of a present value of the fore/aft trim angle, and providingan electrical output in the form of a present trim angle signalindicative of the present fore/aft trim angle of the frame; a depthsensor operatively attached to the implement for indicating a presentdepth of penetration of at least one of the front and rear tillagetools, and providing an electrical output in the form of a present depthsignal indicative of the present depth of penetration of the at leastone tillage tool; and a control unit operatively connected to the depthsensor and the trim angle sensors for respectively receiving theelectrical present depth and present trim angle signals therefrom; thecontrol unit also being operatively connected to the trim angleadjustment power source to provide control thereof for selectivelydriving the trim angle actuator to tilt the frame along the fore/aftaxis to thereby change the present fore/aft trim angle of the frame; thecontrol unit being further configured for receiving a desired depthinput and controlling the trim angle actuator to provide a desiredfore/aft trim angle of the frame corresponding to the desired depthinput signal.
 8. The implement of claim 7, wherein the control unitselects a predetermined trim angle corresponding to the desired seedbeddepth input and controls the trim angle actuator power source using thepredetermined trim angle.
 9. The implement of claim 7, wherein thecontrol unit computes a desired trim angle corresponding to the desireddepth input and controls the trim angle actuator power source using thecomputed trim angle.
 10. The implement of claim 9, wherein the desireddepth input is an incremental adjustment to a present depth ofpenetration.
 11. The implement of claim 7, wherein the trim angleadjusting actuator is a hydraulic cylinder, and the trim angle adjustingpower source is an electrically controlled hydraulic power source. 12.The implement of claim 11, wherein the hydraulic cylinder defines apresent cylinder stroke, and the trim angle position sensor indicatesthe present trim angle by detecting a present absolute position of thepresent cylinder stroke.
 13. The implement of claim 7, wherein the trimangle adjusting actuator is an electrically driven linear actuator, andthe trim angle adjusting power source is an electrical power source. 14.The implement of claim 13, wherein the electrically driven linearactuator defines a present stroke length thereof, and the trim angleposition sensor indicates the present trim angle by detecting a presentabsolute position of the present linear actuator stroke.